Sufism [Taṣawwuf ] is the mystical branch of Islam, inward and esoteric, with strong Indo-Persian roots.
And in High-Sufism the final stage of practice and fulfillment is termed Fana-al-Fana: ‘The Annihilation of Annihilation itself’.
A Self-Eating Expression, naturally. It’s hard to to get away from this monkey.
There are various categories of progress towards Fana and categories within Fana itself. The usual mystics love for and insistence of exclusive ‘Stages of Denouement’.
Sufism is often identified in counterpoint to the literal and puritanical persuasions of the Indian Deobandis, Egyptian Salafists and Saudi Wahabists. The roots of these traditions are political more than religious.